JPS54112154A - Carrier regenerating circuit - Google Patents

Abstract

PURPOSE:To obtain a carrier regenerating circuit which compensates the jitters by providing a method which generates a pulse at the fixed position of a receiving signal, a voltage control oscillator which generates a signal of a frequency N-times as high as a carrier, a phase comparing method, frequency-signal modulating method, etc. CONSTITUTION:As for carrier regenerating demodulation on the AM-PM-VSB modulation system for a facsimile, etc., 1st pulse signal (h) is generated by signal- pulse generator 22 at the fixed position of input signal (a') and then phase-compared 23 with N-multiplication frequency signal (i) of a carrier oscillated by voltage- controllable oscillator 25, and the comparison output is integrated 24 to obtain signal (k) for controlling oscillator 25, thereby phase-synchronizing signal (i). On the other hand, 2nd pulse signal (l) is generated 26 at the fixed position of the input signal, the phase difference between signals (l) and (i) is detected 27, and its output signal (m) and signal (n) obtained through phase modulation 28 of signal (i) are both outputted. Signal (p) obtained by level-discriminating signal (n) by comparator 29 is divided by (n) to regenerate carrier (b'') with the jitters compensated.